Below is a link to a video from Khan Academy.
It is a lesson on Newton's First Law of Motion and is called

Basic primer on Newton's First Law of Motion.

This tutorial will expose you to the foundation of classical mechanics--Newton's laws. On one level they are intuitive, on another lever they are completely counter-intuitive. Challenge your take on reality and watch this tutorial. There world will look very different after you're done.

Click on the link to view the Basic primer on Newton's First Law of Motion